Various forms of doors and windows are not provided with locks while other doors and windows include ineffective locks. One means of assuring a reasonably tightly locked door or window is to provide a prop structure therefore. The prop structure may be inclined relative to and engaged against a doorknob of a horizontally swingable door, horizontally disposed and abutted against the side of a horizontally slidable door or window which is advanced when the door or window is shifted to an open position, and interposed between the upper edge of the inner window of a double hung window and the under surface of the upper frame of the double hung window. However, various doors and windows of these types require props of different lengths. Accordingly, a need exists for an adjustable length door and window prop which may be utilized to prop various types of doors and windows against being opened.
Examples of previously known door and window props including some of the general structural and operational features of the instant invention disclosed in U.S. Pat. Nos. 190,392, 219,098, 324,083, 467,589, 468,987, 598,405, 825,810, 3,583,743, 4,019,765, 4,036,518 and 4,136,899, as well as Canadian Pat. No. 1,019,016 and West German Pat. No. 1,067,392.